Table 6.

Synoptic table of all recommendations and expert consensus statements.

Recommendation	Expert consensus statement
PICO 1: In adult patients with unruptured intracranial aneurysms does any type of microsurgical or endovascular aneurysm occlusion compared to no aneurysm occlusion improve outcomes?
In adult patients in whom the estimated 5-year risk of aneurysm rupture is higher than the risk of the preventive treatment modality, we suggest preventive aneurysm repair with the treatment modality that is most effective and safe for that particular aneurysm	For adult patients with UIA we suggest assessing such patients within a multidisciplinary setting (i.e. neurosurgery, interventional neuroradiology neurology) at large volume centres (consulting at least 100 UIA patients per year)
Quality of evidence: Very low ⊕
Strength of recommendation: Weak for intervention ↑?
In adult patients with growth of a UIA detected at follow up imaging, we suggest preventive aneurysm repair. However, despite an increased risk of rupture in such patients, this risk remains to be weighed against the risk of treatment complications.	For adult patients with UIA we suggest that the recommendation for versus against preventive aneurysm repair by the multidisciplinary team should be based on:
Quality of evidence: Very low ⊕	– Aneurysm-related risk factors for rupture, that is, UIA size, location and lobulation
Strength of recommendation: Weak for intervention ↑?
	– Risk factors for rupture, that is, previous SAH from a different aneurysm, family history for UIA or SAH, smoking and hypertension
	– UIA growth (1 mm in any diameter) or de novo formation on serial imaging
	– Life expectancy
	– Risk factors for treatment complications, that is, patient age and comorbid disease, aneurysm morphology and complexity and estimated risk of treatment
	In adult patients with UIA who present with clinical symptoms, such as cranial nerve deficits, mass effect and thromboembolic events, we suggest preventive aneurysm repair, taking into account life expectancy and risk of treatment complications
	In asymptomatic adult UIA patients with significant comorbid diseases and/or reduced life expectancy (<5 years), we suggest no preventive aneurysm repair
	In adult patients with UIA we suggest that the final management decision is made in a shared decision-making process between the physician and the patient, based on the recommendation by the multidisciplinary team and patient-related psycho-sociological factors
PICO 2 In adult patients with unruptured intracranial aneurysms does any type of microsurgical occlusion compared to any type of endovascular occlusion improve outcome (decrease proportion of patients remaining dependent on help at time of outcome assessment, decrease case-fatality at time of outcome assessment)?
In adult patients with UIA, we cannot make an overall recommendation that states which UIA treatment modality (either endovascular or microsurgical) is preferred based on the current data.	In adult patients with UIA we suggest that the choice between microsurgical and endovascular treatment should be made in a multidisciplinary setting where the chance of complete aneurysm occlusion and risk of complications of microsurgical and endovascular treatment are openly discussed and compared
Quality of evidence: Very low ⊕
Strength of recommendation: –
In adult patients with UIA, we suggest to take into account, in the choice between endovascular and microsurgical treatment, the following conditions which impact on the risk/benefit profile of the procedures:	In adult patients with UIA we suggest that preventive UIA repair should only be done in centres performing aneurysm treatment in more than 100 patients with ruptured and unruptured aneurysms per year and performing the proposed treatment modality (endovascular or microsurgery) in more than 30 patients with aneurysms (ruptured and unruptured) per year per neurosurgeon or neurointerventionalist
– Increasing age (increased risk of complications for microsurgical treatment)
– Female sex (slightly increased risk for endovascular therapy, strongly decreased risk for microsurgical treatment)
– indication for anticoagulation (strongly increased for microsurgical treatment)
– A broad neck of the aneurysm (increased risk for endovascular treatment), aneurysm calcification (increased risk for microsurgical treatment)
– Location on the posterior circulation (slightly increased risk for endovascular therapy and strongly increased risk for microsurgical treatment)
Quality of evidence: Very low ⊕
Strength of recommendation: –
In adult patients with UIA, we suggest flow diverting stents as a treatment option only if no other endovascular or microsurgical options to occlude the aneurysm (complete occlusion or neck remnant only) at a risk lower than the expected 5-year risk of rupture are available and if the risk of rupture outweighs the risk of treatment with flow diverting stents	In adult patients with UIA in the posterior circulation we suggest endovascular treatment as the first option to consider
Quality of evidence: Very low ⊕
Strength of recommendation: Weak against intervention ↓?
PICO 3 In adult patients with unruptured intracranial aneurysms does any type and frequency of follow-up imaging followed by aneurysm occlusion in case of aneurysm growth or other change compared to no follow-up imaging improve outcome (decrease proportion of patients remaining dependent on help at time of outcome assessment, decrease case-fatality at time of outcome assessment)?
In adult patients with a UIA in whom the risk of treatment complications is higher than the 5-year risk of rupture, we recommend radiological monitoring to detect future UIA growth or morphological change for patients in whom treatment remains an option that were initially observed	In adult patients with UIA undergoing radiological monitoring to detect potential aneurysm growth or morphological change, we suggest that the frequency and duration of follow-up imaging should be based on aneurysm- and patient-related risk factors of growth or rupture and risk of treatment. This should be agreed upon in a shared decision-making process between physician and patient based on the recommendation by the multidisciplinary team and patient-related psycho-sociological factors.
Quality of evidence: Very low ⊕
Strength of recommendation: Strong for intervention ↑↑
In adult patients with a UIA that shows recent growth during radiological monitoring, we suggest preventive aneurysm repair. However, despite an increased risk of rupture in such patients, this risk remains to be weighed against the risk of treatment complications.	In adult patients with UIA undergoing radiological monitoring to detect potential aneurysm growth or morphological change, we suggest that radiological follow-up should be continued as long as preventive treatment remains an option
Quality of evidence: Very low ⊕
Strength of recommendation: Weak for intervention ↑?	In adult patients with UIA undergoing radiological monitoring to detect potential aneurysm growth or morphological change, we suggest that radiological follow-up should be performed with MRA or CTA
PICO 4: In adult patients with unruptured intracranial aneurysms does any life-style modification or any medical treatment (e.g. anti-inflammatory drugs, antihypertensive drugs, statins) in comparison to no treatment improve outcome (increase QALY’s, decrease proportion of patients remaining dependent on help at time of outcome assessment, decrease case-fatality at time of outcome assessment)?
In adult patients with UIA who smoke, we recommend smoking cessation	For adult patients with an UIA who do not undergo preventive occlusion, we suggest that there is no contra-indication for platelet aggregation inhibitors if needed for another indication
Quality of evidence: Very low ⊕
Strength of recommendation: Strong for intervention ↑↑
In adult patients with UIA and hypertension, we recommend treatment of increased blood pressure	For adult patients with an UIA who do not undergo preventive occlusion, we suggest keeping blood pressure <130/80 mm Hg
Quality of evidence: Very low ⊕
Strength of recommendation: Strong for intervention ↑↑
In adult patients with UIA, we suggest to not start treatment with acetylsalicylic acid to decrease the risk of aneurysm growth or rupture	For adult patients with an UIA who do not undergo preventive occlusion, we suggest that no restrictions should be imposed regarding sexual activity or any physical or sporting activity
Quality of evidence: Very low ⊕
Strength of recommendation: –
In adult patients with UIA, we suggest to not start treatment with statins to decrease the risk of aneurysm growth or rupture
Quality of evidence: Very low ⊕
Strength of recommendation: –
PICO 5: In adult patients with occluded unruptured aneurysms, does any type and frequency of follow-up imaging compared to no follow-up imaging improve outcome (increase in QALYs)?
For adult patients with a treated UIA in whom aneurysm re-treatment remains an option, we suggest an initial radiological follow-up 3 to 12 months after UIA repair to detect potential UIA remnants or recurrence	We suggest that MR-angiography should be the primary tool for follow up imaging of endovascularly treated aneurysms, CTA for microsurgically treated aneurysms that DSA should only be considered if MRA and CTA are not conclusive
Quality of evidence: Very low ⊕
Strength of recommendation: Weak for intervention ↑?
In adult patients with a treated UIA and recurrence of the aneurysm, we recommend that the pros and cons of re-treatment in the short-term versus a future radiological follow-up are agreed upon in a shared decision-making process between the physician and patient based on the recommendation by the multidisciplinary team and patient-related psycho-sociological factors
Quality of evidence: Very low ⊕
Strength of recommendation: Strong for intervention ↑↑